The broadcast services comprise so-called national services that are to be transmitted to all regions and regional services specific to each region. A single stream is used to transmit the national and regional services. This single stream may, for example, be transmitted via a satellite broadcast. Each region is covered by one or more transmitters called deconcentrators, which receive the single stream transmitted by a single source called a concentrator. This single stream contains all the services. The deconcentrators withdraw from it the national services and the regional services specific to their region in order to form and transmit the so-called regional stream intended to be received by the terminals of the users in the region concerned. The broadcasting can be done for example according to the DVB-H (Digital Video Broadcasting—Handheld) standard defined in the document “ETSI EN 302 304, DVG-H-Transmission System for Handheld Terminals”. The broadcasting of services within the same region is done on the same frequency according to a so-called SFN (Single Frequency Network) system. Such broadcasting involves good synchronisation between the various modulators transmitting the stream on the single frequency within the region. Where these modulators are supplied by several deconcentrators, these must also be properly synchronised. Moreover, the bandwidth available on a satellite is limited and expensive.